Volume 32, Issue 5 (September 2009)
Evaluation of Practical Procedure for Compaction Density and Unit Weight of Rockfill Material
A compaction control procedure for rockfill is proposed on the basis of a method devised for determination of the maximum density of a mixture of soil, gravel, cobbles, and boulders. The procedure is straightforward and involves compaction of rocks (gravel, cobbles, and boulders) separately and compaction of the soil fraction in the usual manner. Only one compaction test is necessary for the rocks because the minimum void ratio for rocks is insensitive to water content. Mathematical formulas are given to calculate the maximum dry density (or unit weight) of the rockfill. These formulas depend on the relative amounts of soil and rocks in the total sample. If the grain size distribution curve is shallower than that for the “maximum density grading curve,” which is often the case for rockfill, then the distinction between soil particles and rock particles is relatively unimportant because the smaller particles fit in the voids between the larger particles.